How to select an excel data Table using a drop downlist value - vb.net

Question

I am working on an application that uses excel files as its data source. I would love the DataGridView to populate with the columns of a sheet when a worksheet name is selected from the drop down list.
Here is what I have tried doing:
Imports System.Data.OleDb
Public Class Form101
Public cn As New OleDbConnection
Public cm As New OleDbCommand
Public da As OleDbDataAdapter
Dim comb As String
Public dt As New DataTable
Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles Comb1.SelectedIndexChanged
comb = Comb1.SelectedText
End Sub
Public Sub FillDataGridView(ByVal Query As String)
da = New OleDbDataAdapter(Query, cn)
dt.Clear()
da.Fill(dt)
With DataGridView1
.DataSource = dt
.Columns(0).HeaderText = "Date"
.Columns(1).HeaderText = "Qty brought"
.Columns(2).HeaderText = "Qty sold"
.Columns(3).HeaderText = "Goods balance"
.Columns(1).AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill
End With
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
cn.ConnectionString = "provider=Microsoft.Jet.OLEDB.4.0; Data Source=C:\toojah app\Stock card.xls; Extended Properties= Excel 8.0;"
cn.Open()
FillDataGridView("select * FROM ['" & comb & "'] ")
End Sub
End Class

Answer 1

Try something like this. The first function will collect all of the columns and records in your excel file and place it into a datatable. Then If you wanted to add additional columns to the datable you can do it in the Public Sub CreateDataGridView. This has been tested and works.
Friend Shared Function BuildDatatable () as datatable
Dim dt As New DataTable
Dim Conn As System.Data.OleDb.OleDbConnection
Dim cmd As System.Data.OleDb.OleDbDataAdapter
dim MyFile as string = "C:\toojah app\Stock card.xls"
Conn = New System.Data.OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + MyFile + ";Extended Properties='Excel 12.0;HDR=YES;IMEX=1';")
Conn.Open()
Dim dtSheets As DataTable = Conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, Nothing)
Dim listSheet As New List(Of String)
Dim drSheet As DataRow
For Each drSheet In dtSheets.Rows
listSheet.Add(drSheet("TABLE_NAME").ToString())
cmd = New System.Data.OleDb.OleDbDataAdapter("select * from [" & drSheet("TABLE_NAME").ToString() & "]", Conn)
cmd.TableMappings.Add("Table", "Net-informations.com")
cmd.Fill(dt)
Conn.Close()
Next
Return dt
Catch ex As Exception
Return Nothing
End Try
End Function
'This is used to pass the function datatable as a dt to then pass to the public sub as shown below.
Dim dt As DataTable = BuildDatatable
Public Sub CreateDataGridView(dt)
Dim newColumn As New Data.DataColumn("ComeColumnName", GetType(System.String))
newColumn.DefaultValue = "YourValues"
dt.Columns.Add(newColumn)
DataGridView1.DataSource = dt
End Sub